1. Field of the Invention
The invention relates to the field of sewage treatment and environment protection, and more particularly to a reactor for low-carbon treatment of sewage.
2. Description of the Related Art
Biological aerated filter (BAF) is a new technology for sewage treatment using biofilm. BAF integrates the biological oxidation and retention of suspended solid as a whole to save the space of the subsequent sedimentation tank, and is characterized in the high volume load, high hydraulic load, short hydraulic retention time, good quality of effluent, and low energy consumption. However, after a period of operation, the interception of the pollutants in the filter layer and the growing of the biofilm easily cause the obstruction of the filter layer, so that the biological aerated filter is required to backwash, which results in waste of a large volume of the water for backwashing and a large head loss.
Artificial wetland is a comprehensive ecological system, it employs principles including species symbiosis and matters recycling in the ecological system and is based on the premise of facilitating the virtuous cycling of the pollutants to fully take advantage of the production potential of the resource, whereby preventing the environment from being further polluted and acquiring a best result of the sewage treatment and sewage utilization as a resource. The artificial wetland functioning as a sewage treatment system is advantageous in its stable quality of the effluent, simple procedure, and low cost in infrastructure and operation, but the system also has problems, such as the effect of removal of nitrogen and phosphorus is not good and the efficiency thereof decreases during winter.
Purpose of the low-carbon treatment of sewage is to control the discharge of greenhouse gases including nitrous oxide. It is indicated from the research results that a high concentration of dissolved oxygen (>0.5 mg/L) in the nitrification, the elimination of dissolved oxygen, and a large COD/N value (>3.5), a relative large SRT value (>10 d), and a proper pH value (between 6.8 and 8) in the denitrification are conducive to the reduction of the production of the nitrous oxide.